FR2881990A1 - FILM FOR THE PROTECTION OF AXLES - Google Patents

Abstract

Film (A) for the protection of powered axle (I), comprises: a first layer (Ia) comprising a compound of aluminum and elastomers, and an adhesive compound, which is deposited on the compound, where (Ia) is adhered with (I); and a second layer (Ib), comprising the adhesive compound in pasty form of cement type, applied to the face of (Ia) not comprising adhesive compound.

Description

Film for axle protection

  The present invention relates to a film for the protection of axles, in particular for rail vehicles, having anti-shock properties and anti-corrosion properties.

  Running gear such as wheels, axles, wheelsets or axle boxes are permanently subject to mechanical problems related to different physical phenomena.

  Axles are generally divided into several classes according to the physical conditions to which they are subjected. Class 1 axles are used for train speeds of over 200 km / h and are subject to atmospheric corrosion and severe mechanical shock. These mechanical shocks can be due to the projection on the axle of projectiles of different sizes and in particular pieces of ballast. Shocks from such projectiles occur at speeds of up to 200 km / h. These shocks can damage the axle which can cause the appearance of cracks as well as its break in its connection fillet.

  To avoid these disadvantages, class 1 axles are generally covered with antiballast protection. This protection protects the axle from shocks and wear due to atmospheric corrosion. This protection consists in applying a polyurea coating to the axle by spraying at a pressure of 130 to 160 bars. The coating results from the condensation between a polyamine-based resin and an isocyanate hardener. This coating dries quickly and is very difficult or impossible to remove for the examination of the condition of the axle at the time of a revision of it by a magnetoscopy operation or by ultrasonic examination. The removal of the coating indeed requires its cutting over the entire length of the axle.

  Because of the adhesion of the coating on certain parts of the axle, it is necessary to scrape the coating several times in order to be able to remove it homogeneously. This can cause cracks in the axle causing damage.

  Such a coating can also become detached at certain points of the axle because of the stresses due to the temperature, which can cause the appearance of cracks as well as the damage of the axle due to repeated shocks caused by projections. pieces of ballast.

  In addition, the application of this spray coating requires the installation of a specific paint booth. In addition, this coating must have antiballast properties for thicknesses greater than 5 millimeters, which forces the operator to make several successive passes to obtain satisfactory antiballasts properties. These successive passes increase the immobilization time of the axle. The drying time of the coating is very short and the coating is difficult to remove, the coating application equipment must be cleaned very quickly using very aggressive solvents resulting in the release of volatile organic compounds that may be harmful to health operators.

  Class 2 and 3 axles are used for rail vehicle speeds below 200 km / h. Class 2 axles are subject to the action of specific corrosive products. Class 2 axles may be used, for example, for wagons carrying goods or as motor drives. Class 3 axles are subjected to atmospheric corrosion and are used in particular for passenger vehicles. These axles are also subjected to various light shocks due to projectiles, including chippings and pieces of ballast. Shocks from such projectiles occur at speeds below 200 km / h.

  To avoid these drawbacks, the class 2 and 3 axles are coated with a water-thinnable paint system generally sprayed at a pressure greater than 140 bars. This layer of paint is difficult to remove without the implementation of a chemical etching or shot blasting process which makes the examination of the condition of the axle more difficult by a magnetoscopy operation or by an ultrasound examination. . The removal of the paint layer results in the rejection of strippers or solvents that may be harmful to the health of operators.

  Thus, the various coatings currently used to protect the different categories of axles have a number of disadvantages.

  In view of the above, the invention aims to effectively protect the axles, whatever their category, against the different attacks to which they are subject, while facilitating the various examinations of the state of the axle.

  To this end, the Applicant has found, surprisingly, that by using a special adhesive film for the protection of the different classes of axles, it was possible to obtain a film which has improved anti-shock properties and which is furthermore easily removable. remove.

  In particular, the film for the protection of axles according to the invention can be easily removed by the application of a biodegradable solvent which makes it possible to carry out an examination of the state of the axles at the time of a revision by an operation of magnetic particle or ultrasound examination.

  The Applicant has also found that the elimination of the film does not involve the release of measurable volatile organic compounds.

  In addition, the film for the protection of axles according to the invention can be used on axles of different classes to protect them both against projections of pieces of ballast at speeds above 200 km / h and against shocks light weight, from chippings or pieces of ballast thrown at speeds below 200 km / h, as well as from the different types of corrosion to which these axles may be subjected.

  The film for the protection of axles according to the invention also makes it possible to reduce the immobilization times of the axles thanks to a zero drying time of the film, unlike the coatings of the state of the art.

  In addition, the application of a film for the protection of axles according to the invention makes it possible to control the thickness of each of the layers thus reducing the immobilization time of the axle.

  According to one embodiment, a film for the protection of axles comprises at least: a first layer, capable of adhering to the axle, comprising a compound chosen from aluminum and elastomers, and on which is deposited an adhesive compound, and a second layer, comprising at least one putty-like paste-like adhesive compound applied to the face of the first layer that does not comprise an adhesive compound.

  In this way, the film has in particular anti-shock properties against chippings and the projection of pieces of ballast at speeds below 200 km / h and is easy to remove.

  For the purposes of the invention, the term "adhesive compound" is intended to mean a compound which makes it possible for the first layer to adhere to the axle.

  Those skilled in the art may choose the adhesive compounds from among the various compounds of the state of the art with adhesive properties. Preferably, he may choose an acrylic glue or a vinyl glue. The adhesive compound deposited on the first layer may be in various forms, in particular in the form of a layer or in the form of pulverized particles.

  An adhesive compound in pasty form of mastic type within the meaning of the invention is understood to mean an adhesive compound whose consistency is neither liquid nor solid at a temperature of 20 C.

  According to another advantageous embodiment, the film for protecting axles according to the invention comprises an adhesive compound comprising at least one anticorrosive pigment.

  In this way, the film can present for the different classes of axles both anti-shock properties, especially against gravel or pieces of ballast projected at speeds of less than 200 km / h, and anti-corrosion properties.

  For the purposes of the invention, the term "gravel" means a set of particles or materials capable of having a size ranging from 20 mm to 4 cm.

  Ballast pieces within the meaning of the invention are understood to mean pieces of angular hard material generally crushed, the dimensions of which are between 4 and 10 cm and which are intended for the infrastructure of the railway tracks.

  According to another advantageous embodiment, the film for protecting axles may further comprise a third layer, applied to the second layer, and comprising at least one elastomer and / or at least one thermoplastic or thermosetting material.

  In this way, the film can advantageously present for class 1 axles both antiballasts properties, due to the presence of this third layer, and anticorrosion properties due to the presence of at least one anticorrosion pigment in the adhesive compound the first layer likely to adhere to the axle in the case where it replaces a paint system. The film thus makes it possible to protect the class 1 axle from pieces of ballast that can be projected at a speed ranging from 200 km / h to 700 km / h.

  According to another characteristic of the invention, the anticorrosive pigment may be chosen from barium metaborate, zinc phosphate, zinc, basic lead silico chromate, zinc tetraoxychromate, zinc chromate and strontium chromate. , red iron oxide, yellow iron oxide and chromium phosphate.

  These pigments can be in the dry state in the form of a fine powder or in the liquid state. These anticorrosion pigments may be present in an amount of less than 5% by weight relative to the total weight of the adhesive compound.

  According to yet another characteristic of the invention, the film for the protection of axles comprising a layer capable of adhering to the axle comprises aluminum.

  Aluminum has the advantage of having good tensile properties which will make it possible to be able to deform more easily the aluminum adhesive layer and thus be able to cover the axle over its entire surface. In addition, the aluminum adhesive layer will facilitate the removal of the film from the axle for examination thereof by a magnetic particle or ultrasonic axle examination. The film can be advantageously removed without tearing the aluminum adhesive layer.

  The aluminum adhesive layer also protects the axle of any projectile that could have penetrated the previous layer or layers. This layer preferably has a thickness of less than five tenths of a millimeter. This small thickness will allow the aluminum adhesive layer to deform and come to wind the axle more easily.

  According to another characteristic of the invention, the adhesive compound of the layer capable of adhering to the axle is chosen from an acrylic or vinyl adhesive.

  The paste-like adhesive compound of putty type of the second layer, because of its adhesive nature can adhere to the first layer. In the case of a film having at least three layers, this compound allows adhesion between the first and the third layer, without adding sticky product.

  Advantageously, the paste-like adhesive compound of the mastic type of the second layer may be butyl mastic, in particular that sold under the name T1520 by the company OLIN.

  Butyl sealant is a pasty and sticky material that retains its properties over time. The layer of butyl mastic will allow to dampen shocks and will slow the projectiles, chippings and / or pieces of ballast, so that they strike the first layer likely to adhere to the axle with a speed more low. The butyl mastic layer preferably has a thickness which may be of the order of one millimeter.

  Advantageously, the elastomer of the third layer is chosen from polyurethane, silicones, rubber, polyisobutylene and polybutadiene. Preferably, the elastomer of the third layer is polyurethane. The polyurethane layer preferably has a thickness which may be of the order of 2 millimeters.

  According to another characteristic of the invention, the polyurethane comprises filler materials chosen from rubber pieces, fibers such as glass fibers and / or beads such as glass beads. These filler materials such as rubber pieces improve the antiballast properties of the elastomeric layer. The pieces of rubber may be in the form of crushed materials with a particle size ranging from 1 to 6 mm. Advantageously, the filler materials such as glass fibers make it possible to impart a mechanical strength to the elastomer layer thus preventing this layer from tears. The fillers may have a size ranging from 12 m to 6 mm. The fillers may be present in an amount of between 10% and 60% by weight relative to the total weight of the polyurethane layer. According to yet another embodiment, the third layer may comprise a material for soundproofing the noises. due to the vibrations of the axle. This material may be barium sulfate.

  The invention also relates to the use of a film according to the invention for the coating of railway vehicle axles. Films for the protection of axles which have both anti-shock properties, against gravel or pieces of ballast projected at a speed of less than 200 km / h, and anti-corrosion properties are preferably used for the coating of axles class 2 or 3. Films for the protection of axles which have both anti-shock properties, against ballast pieces projected at a speed greater than 200 km / h, and anti-corrosion properties are preferably used for coating of class 1 axles.

  The invention furthermore relates to a method of coating axles, in particular axles of class 2 or 3. The method consists in applying to the axle a film as described above, and in particular a film having properties shockproof, against gravel or ballast pieces projected at a speed of less than 200 km / h, and anti-corrosion properties.

  The invention also relates to a coating method for axles, in particular class 1 axles. The method consists in applying to the axle a film as described above, and in particular a film having antiballast properties and anticorrosive properties. Advantageously, the ends of the film are connected with a fixing means at the edges of the third layer.

  In the case of a class 1 axle, the axle can be painted before application of the film with an anticorrosive paint, to improve the anticorrosive effect.

  Other features and advantages of the invention will become apparent from the detailed examination of three embodiments taken as non-limiting examples of a film for the protection of axles according to the invention and illustrated by the appended drawings. in which: Figure 1 shows a cross section of a film for the protection of axles according to a first embodiment.

  FIG. 2 represents a cross section of a film for the protection of axles according to a second embodiment and on which the elements identical to those of FIG. 1 bear the same references.

  3 shows a cross section of a film for the protection of axles according to a third embodiment and on which the elements identical to those of FIG. 2 bear the same references.

  As illustrated in FIGS. 1 to 3, a film 1 for the protection of axles according to the invention is intended to coat axles of a railway vehicle of any category to protect them effectively against the different attacks to which they are subjected, while facilitating the various examinations of the axle.

  In a first embodiment as shown in Figure 1, the film 1 for the protection of axles comprises an adhesive layer of aluminum 2 capable of adhering to the axle on its face 2a comprising an acrylic adhesive. The film 1 further comprises a layer 3 of butyl mastic applied on the face of the aluminum adhesive layer 2 not comprising the acrylic adhesive.

  In order to prepare the aluminum adhesive layer 2, a 425/227 aluminum tape sold by the company 3M is used and the aluminum strip 2a is sprayed with acrylic glue comprising zinc phosphate. The zinc phosphate content is less than 5% by weight relative to the total volume of the acrylic glue. The surface 2a of the aluminum strip comprising the acrylic glue and the zinc phosphate is then dried by infrared radiation for a few minutes.

  After drying, an aluminum adhesive layer 2 is obtained which can be cut into the desired different dimensions. An aluminum adhesive layer 2 less than five tenths of a millimeter thick is used. This layer, thanks to its thickness and the good tensile properties of aluminum, will be able to easily deform.

  The second layer 3 made of butyl mastic is prepared and applied to the face of the aluminum adhesive layer 2 not containing the acrylic adhesive. The layer 3 made of butyl mastic has a thickness of the order of one millimeter. Due to the stickiness of the butyl mastic, this layer adheres easily on the aluminum adhesive layer 2. The layer 3 of butyl mastic can advantageously be coated with a polyethylene film. Such a film makes it possible to protect this layer from the accumulation of dust or projectiles at its surface. It also improves the shockproof properties when it has a thickness of 200 m.

  Film 1 exhibits good anti-shock properties against chippings and pieces of ballasts projected at speeds of less than 200 km / h, as well as good anti-corrosion properties.

  In a second embodiment as illustrated in FIG. 2 and in which the elements identical to those of FIG. 1 bear the same references, the film 1 for the protection of axles further comprises a third layer 4 made of polyurethane applied. on the layer 3 of butyl mastic, which is thus sandwiched between the aluminum adhesive layer 2 and the polyurethane layer 4.

  In order to prepare the aluminum adhesive layer 2, a 425/227 aluminum tape sold by the company 3M is used and the aluminum strip 2a is sprayed with acrylic glue comprising zinc phosphate. The zinc phosphate content is less than 5% by weight relative to the total volume of the acrylic glue. The surface 2a of the aluminum strip comprising the acrylic glue and the zinc phosphate is then dried by infrared radiation for a few minutes.

  After drying, an aluminum adhesive layer 2 is obtained which can be cut into the desired different dimensions. An aluminum adhesive layer 2 less than five tenths of a millimeter thick is used. This layer, thanks to its thickness and the good tensile properties of aluminum, will be able to easily deform.

  The second layer 3 made of butyl mastic is prepared and this layer is applied to the face of the aluminum adhesive layer 2 that does not contain acrylic glue. A layer having a thickness of the order of one millimeter is used. Due to the stickiness of the butyl mastic, this layer adheres easily to the aluminum layer 2.

  The third layer 4 made of polyurethane is prepared. It is applied to the layer 3 of butyl mastic. Butyl mastic, because of its sticky nature, will allow the adhesion of the polyurethane layer 4.

  The film has good antiballast properties as well as good anti-corrosion properties. In addition, the film may exhibit good fire resistance in a specific formulation.

  In a third embodiment as illustrated in FIG. 3 and in which the elements identical to those of FIG. 2 bear the same references, the polyurethane layer 4 comprises filler materials chosen from among the pieces of rubber, the fibers such as glass fibers or beads such as glass beads. The provision of these fillers can be any.

  The fillers are in the form of powder whose particle size can vary between 12 m and 6 mm. The film thus has improved antiballast properties.

  The following examples describe methods of coating axles with a film according to the invention.

  Example 1: Coating process of a class 2 or 3 axle.

  One generally distinguishes in an axle, its right part and its extremities which constitute the fillet of connection of an axle.

  When cracks appear at the level of an axle, they appear in the first place at the level of these fillet days.

  First of all, on the axle connection fillers, an adhesive layer made of aluminum is applied. This layer is applied to the face comprising the acrylic glue so that it adheres to the fillet.

  In a second step, the film is applied to the entire axle, that is to say both on the right side of the axle and at the fillet level, the film illustrated in FIG. two successive layers of aluminum adhesives.

  After having covered the class 2 or 3 axle with the whole of the film 1, an adhesive tape is fixed longitudinally at the edges of the layer of butyl sealant 3, so as to connect the ends of the film 1. This collage will allow the film 1 not to peel off during use. The film 1 can also be prepared directly on the axle by successive layers of the different layers.

  At the time of a review by a magnetoscopy or ultrasonic examination of the condition of the axle, a biodegradable solvent can be applied which will solubilize the glue of the adhesive. After solubilization of the adhesive, the entire film 1 can be removed by pulling on the aluminum layer 2.

  Example 2: Method of Coating a Class 1 Axle In the same way as for the coating method of a class 2 or 3 axle, the aluminum adhesive layer is first applied to the connection fillet. and then applying the film 1, as illustrated in Figures 2 or 3, to the entire axle.

  In this way, the connection fillers have two successive layers of aluminum adhesives. After covering the class 1 axle of the entire film 1, it comes to apply a weld at the edges of the layer 4 of polyurethane. This cold welding is applied manually using a two-component gun, so as to connect the ends of the film. This weld, made of polyurethane, ensures that the film 1 which surrounds the axle can not peel off during use. The film 1 can also be placed directly on the axle by successive layers of the different layers.

  At the time of a review by a magnetoscopy or ultrasonic examination of the condition of the axle, a biodegradable solvent can be applied which will solubilize the glue of the adhesive. After solubilization of the glue, the entire film 1 can be removed by pulling on the aluminum layer 2. This method of solubilizing the glue of the adhesive makes it possible to avoid releases of solvents which may be harmful to health of the operator.

Claims (13)

  Film (1) for the protection of axles, characterized in that it comprises at least: a first layer (2), capable of adhering to the axle, comprising a compound chosen from aluminum and elastomers, and on which is deposited an adhesive compound, and - a second layer (3), comprising at least one paste-like adhesive compound of mastic type, applied on the face of the first layer (2) having no adhesive compound .   2. Thread (1) for axle protection according to claim 1, characterized in that the adhesive compound comprises at least one anticorrosive pigment.   3. Thread (1) for the protection of axles according to claim 1 or 2, characterized in that it further comprises a third layer (4), applied to the second layer (3), and comprising at least one elastomer and / or at least one thermoplastic or thermosetting material.   4. Thread (1) for the protection of axles according to claim 2 or 3, characterized in that the anticorrosive pigment is selected from barium metaborate, zinc phosphate, zinc, basic lead silico chromate, zinc tetraoxychromate, zinc chromate, strontium chromate, red iron oxide, yellow iron oxide and chromium phosphate.   5. Thread (1) for the protection of axles according to claim 2 to 4, characterized in that the anticorrosion pigment is present in an amount of less than 5% by weight relative to the total weight of the adhesive compound.   6. Thread (1) for the protection of axles according to any one of claims 1 to 5, characterized in that the layer (2) capable of adhering to the axle comprises aluminum.   7. Thread (1) for axle protection according to any one of claims 1 to 6, characterized in that the adhesive compound of the layer (2) is selected from an acrylic or vinyl adhesive.   8. Film (1) for the protection of axles according to any one of claims 1 to 7, characterized in that the pasty adhesive compound of the second layer (3) is butyl sealant.   Film (1) for the protection of axles according to any one of claims 3 to 8, characterized in that the elastomer of the third layer (4) is chosen from polyurethane, silicones, rubber, polyisobutylene and polybutadiene.   10. Film (1) for the protection of axles according to any one of claims 3 to 9, characterized in that the elastomer of the third layer (4) is a polyurethane.   Film (1) for the protection of axles according to claim 10, characterized in that the polyurethane comprises fillers (5) selected from rubber pieces, glass fibers and / or glass beads.   12. Film (1) for axle protection according to any one of claims 3 to 11, characterized in that the third layer (4) comprises barium sulfate.   13. Use of a film (1) according to any one of the preceding claims for the coating of railway vehicle axles.